DIANKHA et al. (2016) ICAWA, WP2_S2_18b
Session 02
Influence of climatic variables on Sardinella recruitment dynamique in Senegalese waters Ousmane DIANKHA 1,*, Aliou BA 2, Patrice BREHMER 3, Timothée BROCHIER 3, Modou THIAW 4, Bamol Ali SOW 5, Amadou Thierno GAYE 1, and Hervé DEMARCQ 6 1
Université Cheikh Anta Diop (UCAD), Ecole supérieure polytechnique, Laboratoire de Physique de l’Atmosphère et de l’Océan Siméon Fongang (LPAO-SF), BP 5085, Fann Dakar, Sénégal 2 Université Cheikh Anta Diop de Dakar, IUPA, BP 206, Dakar, Sénégal 3 Institut de Recherche pour le Développement (IRD), UMR 195 Lemar, Dakar, Sénégal 4 Institut Sénégalais de Recherches agricoles (ISRA), Centre de Recherches Océanographiques de DakarThiaroye, PRH, BP 2241, Dakar, Sénégal 5 Université Assane Seck de Ziguinchorn(UASZ), Laboratoire d'Océanographie, des Sciences de l'Environnement et du Climat (LOSEC), UFR Sciences & Technologies, BP 523, Ziguinchor, Sénégal 6 Institut de Recherche pour le Développement (IRD), UMR 248 MARBEC (Marine Biodiversity, Exploitation and Conservation), CS 30171, 34203 Sète, France *Correspondance: Tél: (221) 77 447 57 51; Courriel:
[email protected] (O. DIANKHA) Reçu le 13/12/2016; publié le 15/03/2017 AWA © MS WP2_S2_18b
Abstract Several authors, with estimated abundance index, attempted to study the dynamic of Sardinella populations in relation with to their environment fluctuations in West African region. However, this relationship still poorly understood because of the complexity and difficulty to estimate this abundance index that depends on a variable difficult to identify, the fishing effort from artisanal fisheries. This study is a contribution to better understand the link between the variability of environmental conditions and the dynamic of Sardinella aurita and Sardinella maderensis in Senegalese waters using generalized additive model. Recruitment data of these two species estimated from the virtual population analysis model, sea surface temperature, coastal upwelling index, wind speed, surface chlorophyll concentration and north Atlantic oscillation index within 2004-2013 period were used. Our results showed that recruitment of these two small pelagic species are closely linked to changes in the climatic variables tested. However, variables playing the most critical roles differ from one species to another. For the S. aurita, the index of coastal upwelling is the most important factor, while for S. maderensis is the SST which plays the leading role. This study also reveals the existence of temperature, intensity of upwelling, wind speed, concentration of chlorophyll-a and north Atlantic oscillation index thresholds above or below which Sardinella recruitment success is low. Keywords: climatic variables, Sardinella, Senegalese waters, recruitment. 39
Trilateral German-French-African research initiative
EDITED BY: Patrice BREHMER (IRD-France; Dakar), Babacar BA (CSRP, Sub-Region; Banjul) & Gerd KRAUS (TI, Germany; Hamburg). TECHNICAL SUPPORT: Marie Madeleine GOMEZ (CSRP), Ndague DIOGOUL (IRD-UCAD). WITH THE COLLABORATION OF: Bamol Ali SOW , Alban LAZAR, Heino FOCK, Xavier CAPET, Aka Marcel KOUASSI, Idrissa Lamine BAMY, Osvaldina SILVA, Eric MACHU, Vamara KONE, Moustapha DEME, Didier JOUFFRE, Joern SCHIMDT, Modou THIAW, Suzanne TRAORE, Abdoulaye DIOP, Justine DOSSA, Didier JOUFFRE, Ibrahima DIALLO, Arnaud COMOLET, Zacharie SOHOU, Hamet DIADHOU, Célestin BLE, Rafael ALMAR, Moussa SALL, Abou BAMBA, Dano J.A. ROELVINK, Ibrahima LY, Marie BONNIN , Dienaba Beye TRAORE, Adama MBAYE, Hassane Dedah FALL, Mohamed M’barek O. SOUEILIM. ISBN: 978-2-9553602-0-5 Sub Regional Fisheries Commission / Commission Sous Régionale des Pêches ©2017 COVER DESIGN: AWA (BMBF – IRD) project LOGO AND FLYERS: Laurent CORSINI (IRD) TRANSLATION: Amadou NDIONE (independent) SPONSORS ICAWA 2016
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